Shares of Kansas City Southern /zigman2/quotes/200211518/composite KSU +0.62% soared 19% toward a record in premarket trading Tuesday, after Canadian National Railway Co. /zigman2/quotes/208205632/composite CNI +0.91% /zigman2/quotes/203746923/delayed CA:CNR +0.93% announced what it called a "superior proposal" to acquire the railroad operator in a cash-and-stock bid valued at $33.7 billion. Plans for the buyout bid was previously reported by The Wall Street Journal . which would top Canadian Pacific Railway Ltd.'s /zigman2/quotes/204163517/composite CP +1.50% /zigman2/quotes/205690198/delayed CA:CP +1.46% previously agreed on buyout bid. Canadian National said its bid is valued at $325 for each Kansas City Southern share outstanding, a 27% premium to Monday's closing price of $256.40. Under terms of Canadian National's bid, Kansas City Southern shareholders would receive $200 in cash and 1.059 Canandian National shares for each Kansas City Southern share they own. In March, Kansas City Southern had agreed to be acquired by Canadian Pacific in a deal valuing the stock at $275 each and the company at about $25 billion. Kansas City Southern's stock has run up 25.6% year to date through Monday, while the Dow Jones Transportation Average /zigman2/quotes/210598063/realtime DJT +0.69% has advanced 18.3% and the Dow Jones Industrial Average /zigman2/quotes/210598065/realtime DJIA +0.68% has gained 11.3%.